Safety device for bonnets comprising an electric drive and lockable actuator

ABSTRACT

The invention relates to a safety device (1) for a motor vehicle, said device having: a bonnet (2) with an open position and a closed position; and a bonnet lock (3) with a lock retainer (10; 71), the bonnet lock (3) having: a rotary latch (4) with a preliminary locking position and a main locking position, in which the bonnet (2) is locked and closed; and an electric drive (5), which shifts the rotary latch (4) from the main locking position into the preliminary locking position. The lock retainer (10; 71) has an actuator (41; 72), wherein in a first position of the actuator (41; 72) and in the preliminary locking position of the rotary latch (4) the lock retainer (10; 71) engages with the rotary latch (4) and the bonnet (2) is locked and in a second position of the actuator (41; 72) the lock retainer (10; 71) is released by the rotary latch (4) and the bonnet (2) is unlocked. The bonnet (2) is coupled to the actuator (41; 72) such that in the preliminary locking position of the rotary latch (4) a displacement of the bonnet (2) towards the closed position of the bonnet (2) causes a displacement of the actuator (41; 72) from the first position into the second position.

The invention relates to a safety device for a motor vehicle, which has a front hood with an open position and a closed position and a hood latch with a striker.

Such a safety device is known from DE 198 12 835 A 1. The safety device described therein has an arrester hook operating arrangement which is realized by means of a lever construction and in which no rotational constructional elements occur. This safety device is thus characterized by a very simple construction. The front hood is opened from inside the motor vehicle. An opening mechanism is usually realized with the aid of a Bowden cable for opening from the motor vehicle interior. Thus, for example, in DE 10 2007 061 544 A1 an operating lever is described for unlocking a motor hood which is arranged in the passenger compartment and is mechanically connected to a hood latch by means of a Bowden cable. Furthermore, DE 10 2005 044 079 A1 reveals unlocking of a hood latch by means of a Bowden cable.

Use of a Bowden cable has the disadvantage that this needs to be conducted around several components in the engine compartment starting from the vehicle interior to the front area of the front hood, which requires space in the engine compartment and less space is thus available for arrangement of these components in the engine compartment. According to the state of the art, the safety device thus limits options to arrange other components in the engine compartment and is therefore impractical from a manufacturing and constructional perspective. Use of the Bowden cable to open the front hood is also impractical for an operator as he must search for one end of the Bowden cable which is usually located beneath a dashboard and can only move the Bowden cable with considerable physical effort. However, use of the Bowden cable facilitates compliance with the required safety standards for front hoods which are generally more exacting than those for the tailgates.

It is therefore a task of the present invention to create a safety device of the type stated above which is more practical compared to a previously known safety device with a Bowden cable conducted through the engine compartment.

According to the invention, this task is solved by a safety device with the characteristics of the patent claim. Advantageous configurations with expedient further formations of the invention result from the remaining patent claims, the description and the figures.

In order to create a safety device which is more practical compared to a previously known safety device, a safety device for a motor vehicle is provided for which has a front hood with an open position and a closed position and a hood latch, whereby the hood latch comprises a catch with a pre-ratchet position and a main ratchet position and an electrical drive. The electrical drive causes switchover of the catch from the main ratchet position into the pre-ratchet position, whereby the front hood is locked and closed in the main ratchet position. Furthermore, the striker has an actuator, whereby the striker engages with the catch and the front hood is locked in a first position of the actuator and in the pre-ratchet position of the catch. In a second position of the actuator, the striker is released by the catch and the front hood is unlocked. Furthermore, the front hood is coupled with the actuator such that in the pre-ratchet position of the catch, a displacement of the front hood in the direction of the closed position causes a displacement of the actuator from the first position to the second position.

The electrical drive can preferably be controlled, switched on and/or switched off and can preferably be rotatably controlled in a first direction and optionally in a second direction which is opposite the first by means of a switch and/or a control device which is connected to the electrical drive by means of at least one cable. In particular, a rotational movement of the electrical drive causes switchover of the catch from the main ratchet position to the pre-ratchet position.

Due to the fact that the electrical drive is connected to the switch and/or the control device by means of a cable, a Bowden cable conducted through the engine compartment to unbolt the front hood can be dispensed with which facilitates the arrangement of other components in the engine compartment. A switch which operates the electrical drive can also be arranged at any position on a motor vehicle dashboard so that the safety device is easier to unbolt and therefore more practical for an operator.

In the main ratchet position the catch is locked in an opening rotational position which is specified by a rotation of the catch from the main ratchet position into the pre-ratchet position and encompasses the striker in such a way that a release of the striker is blocked. The catch has a preferably fork-shaped infeed section which is formed by a load arm and a collecting arm, whereby the infeed section encompasses the striker in the main ratchet position. The striker can generally be viewed as a detachable connecting element between the catch and the front hood which interacts directly with the catch and can be locked and unlocked with the aid of the catch, whereby locking or unlocking of the striker causes locking or unlocking of the front hood.

According to an advantageous configuration, the striker is arranged on the front hood and the catch is arranged on a component of a motor vehicle attached to the chassis. In a different embodiment, the striker can be arranged on a component of the motor vehicle attached to the chassis and the catch can be arranged on the front hood. The greater mass inertia of the front hood can thus reduce a bouncing effect of the front hood which preferably counteracts the load arm of the catch in the pre-ratchet position during closure of the front hood.

By means of the electrical drive of the hood latch an arrangement of the catch on the front hood is considerably easier to execute, as only a cable needs to be conducted along the movable front hood in this embodiment instead of a Bowden cable. An arrangement of the catch on the front hood can be advantageous from a manufacturing perspective to the extent that the catch and the electrical drive can be better mounted on an individual front hood than in an already equipped engine compartment.

The hood latch preferably has a catch blocking element, such as a pawl, which locks the catch in the main ratchet position and/or the pre-ratchet position, whereby locking means a blocking of the catch in the opening rotational direction. Furthermore, it is within the scope of the invention that the catch has a pre-ratchet contour and a main ratchet contour which can interact respectively independently of one another with a counterratchet contour of the catch blocking element during rotation of the catch in the opening rotational direction and into a closure rotational direction which is opposite to the opening rotational direction.

Especially advantageously, the pre-ratchet contour or the main ratchet contour passes the counterratchet contour of the pawl during rotation of the catch in the closure rotational direction. If the pre-ratchet contour or the main ratchet contour is located in front of the counterratchet contour of the pawl viewed in the closure rotational direction, the counterratchet contour preferably ratchets in a spring-impinged manner into the pre-ratchet contour or the main ratchet contour and blocks rotation of the catch in the opening rotational direction, whereby the catch assumes the pre-ratchet position or the main ratchet position. In order to execute this in detail, a catch spring element acts on the catch in the opening rotational direction, whereby the pre-ratchet contour or the main ratchet contour is held pressed against the counterratchet contour in the pre-ratchet position or the main ratchet position accordingly. The catch spring element can be tensioned during movement of the front hood in the direction of the closed position, whereby the striker touches the catch. A tensioned catch spring element can enable an independently driven switchover of the catch from the main ratchet position into the pre-ratchet position, whereby such switchover can be triggered by means of the electrical drive, for example by means of driving of the pawl.

A special configuration envisages that the catch assumes a position with the pre-ratchet position by means of which the catch is immobile in the opening rotational direction, not even by means of detachment of the pawl. In this embodiment, the catch assumes an opening end position with the pre-ratchet position in which a rotation of the catch in the opening rotational direction can be blocked with a static blocking element. In a different embodiment, the catch has an opening end position in which the catch is rotated into the opening rotational direction from the pre-ratchet position. In any case, the catch is engaged with the striker in the pre-ratchet position.

The front hood is closed in the main ratchet position of the catch. Closed means that the front hood is located in the closed position which can be moved in a first direction into an open position and in a second direction, opposite to the first, to the closed position. In particular, it is envisaged when the front hood is closed that an elastic element of the safety device, such as a sealing rubber, which is adjacent to the front hood in the closed position or is arranged on the front hood, is compressed. A front hood for the purpose of the invention means a hood which is arranged in front of a windscreen of the motor vehicle in the direction of the motor vehicle.

In the pre-ratchet position, the catch is blocked in the opening rotational direction, preferably by means of the pawl or the static catch blocking element. If the actuator is located in the first position in this position of the catch, the striker engages with the catch. By means of this engagement, the catch blocks a movement of the front hood in the direction of the open position which corresponds to locking of the front hood.

In the second position of the actuator the striker is released from the catch and a blockage of a movement of the front hood in the direction of the open position is triggered, which corresponds to unlocking of the front hood. The striker can preferably be accommodated or arrested by means of the collecting arm of the catch when the front hood falls shut.

The switchover of the catch from the main ratchet position into the pre-ratchet position is caused by means of the electrical drive according to the invention, which preferably has a pinion shaft. This can be executed in a special configuration by means of a triggering lever which is acted on by means of the pinion shaft of the electrical drive, whereby the triggering lever causes unratcheting of the catch from the main ratchet position during movement of the pinion shaft. For example, the triggering lever can move the pawl against a spring force which acts on the pawl and move the counterratchet contour away from the main ratchet contour or release it from the ratchet position. According to this, causing of the switchover of the catch from the main ratchet position into the pre-ratchet position also encompasses triggering of this switchover for the purpose of the invention.

It is furthermore possible that the triggering lever releases a pre-tensioned force spring during movement of the pinion shaft which unratchets the pawl against its spring impingement. The advantage of this variant is that the electrical drive can have smaller dimensions as only the pre-tensioned force spring needs to be triggered by means of the drive. However, in this configuration an additional gearbox can be necessary to tension the force spring by means of the electrical drive. Advantageously, the force spring can be tensioned during rotation of the catch in the closure rotational direction, preferably assisted by weight force by means of a movement of the front hood in the direction of the closed position.

A further configuration can envisage that the pinion shaft of the electrical drive acts directly on the pawl and during activation of the electrical drive the counterratchet contour unratchets the pawl from the main ratchet contour. The advantage of this configuration is that no transmission element is necessary between the pinion shaft and the pawl, such as a triggering lever.

The electrical drive can, for example, be activated from the vehicle interior or the vehicle exterior by means of remote control. During switchover from the main ratchet position into the pre-ratchet position, the catch preferably moves the front hood in the direction of the open position of the front hood by means of the striker.

According to the invention, the striker has an actuator, whereby the striker engages with the catch and the front hood is locked in the first position of the actuator and in the pre-ratchet position of the catch and the striker is released from the catch and the front hood is unlocked in the second position of the actuator. In a particular embodiment, the catch is located in the pre-ratchet position when the actuator assumes the second position. A different embodiment envisages that the catch is located in a position in which the catch rotates beyond the pre-ratchet position in the opening rotational direction when the actuator assumes the second position.

The actuator is mechanically coupled with the front hood on the one hand and preferably interacts with a locking element of the striker on the other hand, dependent on the position of the actuator. For example, the locking element can be a bolt, a pin or a spigot or an arrangement of such elements, for example an arrangement of two coaxially aligned spigots, whereby the catch encompasses the locking element in the pre-ratchet position and in the first position of the actuator.

In a special embodiment, the actuator can hold the two coaxially aligned spigots apart against a spring force in the first position, whereby the spigots respectively protrude laterally from a shaft of the striker and assume an active position. In this active position of the spigots, the infeed section of the catch encompasses the spigots, whereby the catch is located in the pre-ratchet position. According to this embodiment, the actuator can release space between the spigots in the second position and cause a spring force-drive movement of the spigots into this space. If the spigots occupy this space at least partially, the spigots are located in a passive position in which the spigots are released from the infeed section and the striker thus no longer engages with the catch and is also released. The actuator is preferably shiftably guided between the first and second position within the shaft of the striker.

A special configuration envisages that the actuator is ratchetable and the striker has a control contour and a guide element, whereby the guide element interacts with the control contour such that ratcheting of the actuator is facilitated at least in the first and/or second position of the actuator. In order to realize this, the control contour has at least a first ratchet contour into which the guide element which can be formed as a pin, for example, is ratcheted. In the ratcheted position of the actuator the control contour attacks the guide element such that the guide element at least blocks a movement direction of the actuator, for example a rotation of a central axis of the actuator. A special configuration can also provide for a blockade of the actuator in a direction parallel to the central axis by means of the guide element. Furthermore, the striker preferably has a striker spring by means of which the first ratchet contour can be acted on against the guide element. If the guide element is located in the first ratchet contour, the striker spring is thus tensioned and relaxation of the striker spring is blocked by means of the guide element.

Within the scope of a first variant, the control contour can be arranged on the actuator and the pin on the shaft of the striker. A different variant envisages that the control contour is arranged on the shaft and the pin on the actuator. Advantageously, the control contour has two opposite delimiters, usually running parallel to one another, which form a guide track for the guide element. The control contour extends in the peripheral direction preferably in a zig-zag manner around the actuator and preferably has several ratchet contours into which the guide element can ratchet. Hereinafter it should be assumed in a simplified, but not restrictive, manner that the control contour has a first and second ratchet contour and has a descending section and an ascending section between the two ratchet contours. The first ratchet contour is hereinafter arranged in relation to a cross-section vertically to a central axis of the actuator below the second ratchet contour.

In a descending movement of the actuator in relation to the striker shaft the control contour preferably guides the guide element from the first ratchet contour via the ascending section to the second ratchet contour and during a subsequent ascending movement of the actuator guides the guide element from the second ratchet contour via the descending section to the first ratchet contour.

According to the invention, the front hood is coupled with the actuator such that in the pre-ratchet position of the catch a displacement of the front hood in the direction of the closed position causes a displacement of the actuator from the first position to the second position. A displacement of the front hood in the direction of the closed position can be triggered, for example, by means of an external pressure operation on an area of the front hood aligned upwards, whereby, aligned upwards means a direction running from the catch to an external surface of the front hood. Alternatively, the front hood can also be electrically displaceable by means of a further electrical drive in the pre-ratchet position of the catch, whereby it can operated separately from the electrical drive described above. In an advantageous configuration, a displacement of the front hood in the direction of the closed position causes a downward movement of the actuator, whereby downward means a direction running from the external surface of the front hood to the catch. Advantageously, the hood latch is equipped with a lever which transmits a comparatively large movement of the front hood into a small movement of the actuator. The lever can hereby have a lever ratio of approximately 2 to 20.

In an especially advantageous embodiment the actuator, starting from the first position, in which the guide element is ratcheted in the first ratchet contour, is mobile in the direction of the closed position by means of a movement of the front hood such that the guide element can be pushed out of the first ratchet contour and tensioning of the striker spring is facilitated. A movement of the guide element out of the first and second ratchet contour is generally assisted by means of respectively displaced delimiters of the control contour. During a tensioning of the striker spring a displacement of the actuator is caused in the direction of the second position of the actuator, whereby the guide element glides along the ascending section of the control contour. The striker spring is preferably dimensioned such that it forms a spring force in the tensioned state which is considerably greater than the weight force of the front hood. In the second position of the actuator, the guide element is held in the second ratchet contour in a spring-impinged manner, whereby the ascending section impacts the descending section of the control contour on the second ratchet contour.

Within the scope of an especially preferred variant, the front hood can be adjusted manually in the direction of the closed position in the pre-ratchet position of the catch. Manually adjustable means in particular exclusively mechanically, i.e. without electricity and without electrical aids. The front hood can thus, for example, be displaceable for an operator of the safety device by means of pressure operation on an external surface of the front hood in the direction of the closed position, whereby displacement of the actuator from the first position to the second position can be triggered in particular. In other words, the front hood can be mechanically unlocked by an operator in the pre-ratchet position of the catch. This has the advantage that in the case of misenergization of the electrical drive the front hood is not unlocked, but secured by the catch via the striker.

A further configuration envisages that in the pre-ratchet position of the catch a displacement of the front hood in the direction of the closed position causes a displacement of the actuator from the second position to the first position. For example, the displacement of the front hood in the direction of the closed position can cause relaxation of the striker spring and can move the guide element into the first ratchet contour along the descending section. If the guide element is located in the first ratchet contour the actuator assumes the first position. In this configuration, the striker spring is more relaxed in the first position of the actuator than in the second position of the actuator; however, in both positions of the actuator the actuator impinges with a commutated force, in particular a pressure force, which is preferably greater than the weight force of the front hood, in order to facilitate holding of the guide element in the first or second ratchet contour.

Due to the fact that according to the invention the front hood is locked in the first position of the actuator and the pre-ratchet position of the catch, starting from a closed state of the front hood dual operation of the safety device is provided to unbolt the front hood. On the one hand, activation of the electrical drive to switch over the catch from the main ratchet position into the pre-ratchet position and, on the other hand, a displacement of the front hood in the direction of the closed position, for example by means of a depression of the front hood. This redundancy lends the safety device according to the invention greater safety compared to a safety device without displacement of the front hood in the direction of the closed position or without operation of an electrical drive. This applies in particular if the front hood can be solely manually unlocked in the pre-ratchet position of the catch and in the first position of the actuator which is provided for in the aforementioned configuration.

A further configuration envisages that one displacement of the actuator from the first position to the second position causes detachment of the pawl from the catch. Especially advantageously, during displacement of the front hood in the direction of the closed position the actuator interacts with the pawl and passes the pawl during displacement of the front hood in the direction of the open position without detaching it from the catch.

Within the scope of an especially preferred variant, the safety device has a mechanical operative connection between the electrical drive and the catch during switchover of the catch from the main ratchet position into the pre-ratchet position. Advantageously, the safety device provides a force-transmitting operative connection chain in every intermediate position of the catch between the main ratchet position and the pre-ratchet position starting from the electrical drive via the catch to the striker.

For example, the mechanical operative connection can be formed by means of an output socket gear which is form-fittingly connected to the pinion shaft of the electrical drive and a pinion gear drive which is form-fittingly connected to the catch, whereby the output socket gear combs with the pinion gear drive. A driving of the catch with the aid of the electrical drive during switchover from the main ratchet position into the pre-ratchet position enables lesser dimensioning of the catch spring element, whereby space can be saved in direct proximity to the catch. A special configuration of the safety device can even provide for no catch spring element at all. The electrical drive can preferably be operated in generator mode in order to form mechanical resistance of the catch against a movement of the front hood in the direction of the closed position during arresting of the front hood.

In a further embodiment, the mechanical operative connection can be formed by means of a wormgear which is form-fittingly connected to the pinion shaft of the electrical drive, and a wormgear wheel which is form-fittingly connected to the catch, whereby the wormgear engages into the wormgear wheel. In any case, a mechanical operative connection means that a movement of the pinion shaft directly gives rise to a movement of the catch, i.e. the pinion shaft is mechanically coupled with the catch.

By means of the mechanical operative connection between the electrical drive and the catch it is possible and lies within the scope of the invention that a movement of the front hood in the direction of the open position during switchover of the catch from the main ratchet position into the pre-ratchet position is controllable, i.e. that both an initial acceleration of the front hood and also a decelerating acceleration can be controlled shortly before attainment of the pre-ratchet position of the catch, whereby the initial acceleration and the decelerated acceleration advantageously have a parabola-shaped course over time. For example, the decelerating acceleration can be reduced as the catch approaches the pre-ratchet position, whereby overshooting of the front hood can be minimized after the catch has reached the pre-ratchet position. The front hood is therefore simpler to record and more convenient opening of the front hood can be provided, in particular if an operator is located directly in front of the front hood and activates the electrical drive by means of remote control.

A further configuration of the invention envisages that the safety device has a mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position. The mechanical operative connection can be formed as described above, i.e. for example by means of an output socket gear and a pinion gear drive or by means of a wormgear and a wormgear wheel.

The mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position causes a more powerful and, in particular, a controllable ratcheting of the catch into the main ratchet position compared to the state of the art. A more powerful and in particular a controllable ratcheting of the catch enables realization of a smaller gap dimension between the front hood in the closed state and a further chassis component adjacent to the front hood. Advantageously, a force transmission is provided for from the electrical drive to the catch which increases when the catch approaches the main ratchet position. The elastic element which lies adjacent to the front hood when the front hood is closed can thus be compressed controlled by means of the electrical drive.

Especially advantageously, the catch can be held in a position by means of the mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position in which the main ratchet contour is located directly in front of the counter ratchet contour of the pawl during a ratcheting process in the closure rotational direction. A holding of the catch in this position, for 10 to 100 milliseconds, for example, enables the ratcheting process of the counter ratchet contour into the main ratchet contour to be delayed at will. In contrast, in the safety devices according to the state of the art a pawl spring which moves the counter ratchet contour by means of the pawl into the main ratchet contour must be configured in such a way within a possible ratcheting period which starts with a rotation of the catch in the closure rotational direction with passing of the main ratchet contour on the counter ratchet contour and ends with passing of the main ratchet contour on the counter ratchet contour during rotation of the catch in the opening rotational direction, moves the pawl so quickly that the counter ratchet contour ratchets into the main ratchet contour within the possible ratcheting period. According to a corresponding spring force which needs to be all the greater, the shorter the ratcheting period needs to be. According to the state of the art, a possibility of extending the ratcheting period by a gap dimension between the front hood in the closed state and a further chassis component, for example a front headlight, is increased as the path covered by the main ratchet contour within the ratcheting period is increased. Manual holding of the front hood would be in a position in which the main ratchet contour is located during a ratcheting process in the closure rotational direction directly before the counter ratchet contour of the pawl and the elastic element is compressed is almost impossible with a low gap dimension.

By means of the mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position the duration of the ratcheting period can be increased at will as the catch can be held in any position for any duration by means of the electrical drive. A smaller dimensioning of the pawl spring is thus possible which saves weight and material costs. The gap dimension can also be considerably reduced between the front hood and the further chassis component as the ratcheting period no longer depends on the gap dimension. Such a safety device is therefore more practical from a production and constructional perspective than one according to the state of the art.

Especially advantageously, by means of the mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position and a controlledly compressible sealing element, a gap dimension between the closed front hood and at least a further chassis element, for example a front headlight, can be changed, whereby it is possible to offset manufacturing tolerances which have an impact on a gap dimension between the front hood and the further chassis element. This constitutes a manufacturing simplification. In detail, this can be executed with a main ratchet contour of the catch which can be adjusted along the opening or closure rotational direction. For example, the main ratchet contour can be arranged independently of the pre-ratchet contour on a disk which can be fixed in the opening rotational direction or in the closure rotational direction of the catch by means of ratchet elements. In detail, the ratchet elements can be fixed in adjustable ratchet positions by means of fixing, for example by means of a screw.

Further advantages, characteristics and details of the invention result from the following description of at least a preferred embodiment to which the invention is not restricted, however, and on the basis of figures.

These show:

FIG. 1 a cross-sectional view of a safety device;

FIG. 2 a cross-sectional view of a section of the safety device according to FIG. 1 with a catch in a pre-ratchet position and an actuator in a first position;

FIG. 3 a cross-sectional view of a section of the safety device according to FIG. 1 with a catch in a pre-ratchet position and the actuator in a second position;

FIG. 4 a cross-sectional view of a striker of the safety device according to FIG. 1 with the actuator in the first position and a guide element ratcheted in a first ratchet contour;

FIG. 5 a cross-sectional view of a striker of the safety device according to FIG. 1 with the actuator in the second position and a guide element ratcheted in a second ratchet contour;

FIG. 6 a cross-sectional view of a striker of the safety device according to FIG. 1 with the actuator in the first position and a guide element ratcheted in a third ratchet contour;

FIG. 7 a cross-sectional view of a striker of the safety device according to FIG. 1 with the actuator in the second position and a guide element ratcheted in a fourth ratchet contour;

FIG. 8 a cross-sectional view of a section of the safety device according to FIG. 1 with a further embodiment of an actuator in a first position;

FIG. 9 a cross-sectional view of a section of the safety device according to FIG. 1 with the actuator according to FIG. 8 in an intermediate position;

FIG. 10 a cross-sectional view of a section of the safety device according to FIG. 1 with the actuator according to FIG. 8 in a second position;

FIG. 1 shows a cross-sectional view of a safety device 1 with a front hood 2 and a hood latch 3. The hood latch 3 has a catch 4 and an electrical drive 5 which encompasses a first electromotor 6 and a second electromotor 7. The front hood 2 is closed in the position shown in FIG. 1 by means of solid lines, i.e. it is located in a closed position. In the closed position an elastic element 8, such as sealing rubber which is arranged in the closed position between a component 9 of the safety device 1 attached to the chassis and the front hood 2 is compressed. The open position of the front hood 2 is illustrated in dot dashes in FIG. 1. Furthermore, the safety device 1 has a striker 10 which is arranged on the front hood 2. The catch 4 and a pawl 12 of the hood latch 3 are respectively pivotably arranged on a non-illustrated component rotatably attached to the chassis.

FIG. 2 shows a cross-sectional view of a section of the safety device 1. The catch 4 has a pivot point 23, an opening rotational direction 21 and a closure rotational direction 22 in the opposite direction. Furthermore, the catch 4 has a pre-ratchet contour 24 and a main ratchet contour 25, respectively in the form of a protrusion, and an infeed section 27, which is formed by means of a collecting arm 28 and a load arm 29. The pre-ratchet contour 24 and the main ratchet contour 25 can respectively interact with a counter ratchet contour 26 of the pawl 12.

The catch 4 is shown in a pre-ratchet position in FIG. 2. In the pre-ratchet position the pawl 12 is kept compressed with the aid of a pawl spring element 31, such as a tensioning, compression or spiral spring, in an anti-clockwise direction against the catch 4. Advantageously, the catch 4 is spring-impinged in the pre-ratchet position by means of a catch spring element 32, such as a tensioning, compression or spiral spring, in an opening rotational direction 21, whereby in the pre-ratchet position the pre-ratchet contour 24 is positioned pressing against the counter ratchet contour 26. The front hood 2 is located in the position shown in FIG. 2 in an intermediate position between the open position and the closed position and is locked.

In the position shown in FIG. 1 the catch 4 is located in a main ratchet position. The main ratchet position is reached by the catch 4 being rotated from the pre-ratchet position according to FIG. 2 further in the closure rotational direction 22. In one embodiment, this can be caused by depression of the front hood 2 and in another embodiment by means of a driving of the catch 4 by means of the first electromotor 6. Thus, for example, a torque 6 can be transmitted on a pinion gear drive 35 of the catch 4 by means of an output socket gear 34 of the first electromotor 6, whereby the torque is oriented in the closure rotational direction 22.

A movement of the catch 4 can also be caused in the direction of the main ratchet position by means of a combination of a manual depression and electrical driving of the first electromotor 6. For example, the first electromotor 6 can be activated to drive the catch in the closure rotational direction as soon as a manually triggered movement of the catch 4 is recorded in the closure rotational direction, for example by means of a sensor which can be executed as a multiturn potentiometer. A recording of the movement of the catch 4 in the closure rotational direction can furthermore be facilitated by means of operation of the first electromotor 6 in generator operation, whereby rotation of the catch 4 in the closure rotational direction generates a current flow in the first electromotor 6.

During rotation of the catch 4 in the closure rotational direction 22 up to at least beyond the main ratchet position of the catch 4 the main ratchet contour 25 passes the counter ratchet contour 26 and the main ratchet contour 25 is located in the closure rotational direction 22 viewed in front of the counter ratchet contour 26, whereby the contour ratchet contour 26 can ratchet into the main ratchet contour 24 and the catch 4 subsequently assumes the main ratchet position. Furthermore, FIG. 1 shows a circular brake block attached to the chassis to brake the catch 4 in the closure rotational direction, whereby a play is present between the catch 4 and the brake block in the main ratchet position in order to enable ratcheting of the catch into the main ratchet position.

In the main ratchet position the infeed section 27 encompasses the striker 10 and the pawl 12 blocks a rotation of the catch 4 in an opening rotational direction 21, whereby the front hood 2 is locked, closed and blocked in the direction of the open position. The load arm 29 is preferably arch-shaped. In the case of a frontal impact, in which the catch 4 is pushed relatively to the front hood 2 against the direction of travel, this can cause increased pulling of the front hood 2 in the direction of the catch 4 and thus firmer pressing of the front hood 2 onto a further chassis element, for example the component 9 attached to the chassis and thus reduce a risk of unintentional unlocking of the front hood 2 and provide a more compact and thus crashproof unit consisting of the front hood 2 and the further chassis element. This advantage is provided both by means of an arch-shaped load arm 29 of the catch 4 and by means of the catch 4 as such as a component of the safety device.

After the counter ratchet contour 26 is ratcheted into the main ratchet contour 24, the first electromotor 6 is deactivated, where this was activated to switch over from the pre-ratchet position into the main ratchet position. The first electromotor 6 can be operated in generator mode for a short time to record the catch position, preferably intermittently between motor mode and generator mode, whereby in generator mode a current signal is generated differently from zero, insofar as the catch has not yet reached the main ratchet position. After the catch has assumed the main ratchet position, the catch rests and the current signal reaches a zero value in generator mode. Such an operating mode of the first electromotor 6 enables a sensor for recording the catch position or exact finetuning of the first electromotor 6 to the geometry of the catch 4 to be dispensed with.

Should the front hood 2 be unlocked starting from the main ratchet position, the catch 4 is initially transferred from the main ratchet position into the pre-ratchet position. This is caused in the embodiment shown in FIG. 1 and FIG. 2 by the second electromotor 7 moving the pawl 12 into the release position illustrated in dot dashes in FIG. 2 by means of a pawl output socket gear 36 and a pawl pinion gear drive 33 in which the catch 4 is released in the opening rotational direction.

Advantageously, the first electromotor 6 causes switchover of the catch 4 from the main ratchet position shown in FIG. 1 into the pre-ratchet position shown in FIG. 2, whereby the safety device has a mechanical operative connection during this switchover. The mechanical operative connection is formed by means of an output socket gear 34, which is form-fittingly connected to the pinion shaft of the first electromotor 6, and the pinion gear drive 35 which is form-fittingly connected to the catch 4, whereby the output socket gear 34 combs with the pinion gear drive 35. In this switchover of the catch 4 driven by the first electromotor 6, as described above, intermittent operation of the first electromotor 6 is possible which alternates between motor mode and generator mode, whereby it can be recorded when the catch 4 has reached the pre-ratchet position.

In a different embodiment, the catch 4 rotates from the main ratchet position into the pre-ratchet position in a spring-impinged manner by means of the catch spring element 32 after the pawl 12 has reached the release position. A further configuration can envisage an interacting driving of the catch 4 by means of the electromotor 6 and the catch spring element 32. The theory according to the invention does not inevitably provide for electrical driving of the catch 4 during switchover of the catch 4 from the main ratchet position into the pre-ratchet position. Consequently, an embodiment of the theory according to the invention is also possible without the first electromotor 6. The switchover of the catch 4 from the main ratchet position into the pre-ratchet position is caused in this case by the second electromotor 7 as described above.

In the position of the safety device 1 shown in FIG. 2, the front hood 2 is locked, whereby the load arm 29 encompasses the striker 10 in the pre-ratchet position of the catch 4. Starting from this position, the front hood 2 can be unlocked by means of a displacement of the front hood 2 in the direction of the closed position of the front hood 2. The striker 10 has an actuator 41 to this end, which is coupled with the front hood 2 such that in the pre-ratchet position of the catch 4 the displacement of the front hood 2 in the direction of the closed position of the front hood 2 causes an adjustment of the actuator 41 from a first position as shown in FIG. 2 to a second position as shown in FIG. 3. The actuator 41 is shiftably guided in a shaft 42 of the striker 10 for such a displacement. The first and second position of the actuator 41 must be understood as relative positions in relation to the shaft 42 of the striker 10. In the embodiment shown in FIG. 2 and FIG. 3 the catch 4 is located in the pre-ratchet position if the actuator 41 assumes the first and the second position.

In the pre-ratchet position of the catch 4 the actuator 41 can be moved compared to the shaft 42, whereby a locking element 43 of the catch 4 releases a space between a pin 44 firmly arranged on the actuator 41 and a counterpin 45 firmly arranged on the shaft 42. In the main ratchet position shown in FIG. 1, the locking element 43 blocks a relative movement of the pin 44 to the counterpin 45 and thus a relative movement between the actuator 41 and the shaft 42. The catch 4 assumes a two-stage locking function in this embodiment. In a first step, the catch 4 blocks a movement of the shaft 42 of the striker 10 and a relative movement of the shaft 42 compared to the actuator 41 in the main ratchet position. In a second step, in the pre-ratchet position the catch 4 blocks a movement of the shaft 42 insofar as the actuator 41 assumes the first position and releases the relative movement of the shaft 42 compared to the actuator 41.

FIG. 4 shows a cross-sectional view of the striker 10 with the actuator 41 in the first position and the catch 4 in the pre-ratchet position. The striker 10 has a control contour 51, a die 52, a tension spring 54 and a locking element in the form of two shiftable round spigots 53 accommodated coaxially in the shaft 42. In the first position of the actuator 41 the die 52 holds the spigots 53 against a tensile force of the tension spring 54 at a distance from one another so that the spigots 53 protrude laterally out of the shaft 42 and are encompassed by the load arm 29 of the catch 4. In this position of the spigots 53 the striker 10 is engaged with the catch 4 and the front hood 2 is locked.

FIG. 5 shows a cross-sectional view of the striker 10 with the actuator 41 in the second position and the catch 4 in the pre-ratchet position. In the second position, the actuator 41 is shifted relatively to the shaft 42 in the direction of the catch 4 in contrast to the first position. Furthermore, in the second position of the die 52 a space 55 is freed between the spigots 53 in which the tension spring 54 tensioned in the first position of the actuator 41 pulls in the spigots 53.

In the compressed state of the spigots 53 the spigots 53 are accommodated in the shaft 42 and assume a passive position in which the spigots 53 are released from the load arm 29 and thus the striker 10 from the catch 4 and the front hood 2 is unlocked.

The control contour 51 arranged on the actuator 41 interacts with a guide element 57 firmly arranged on the shaft 42 in the form of a pin such that in a movement of the actuator 41 from the first position to the second position and vice versa the actuator 41 rotates around a central axis 56 of the actuator 41 and ratcheting of the actuator in the first and second position is enabled. In order to provide a rotatable accommodation of the actuator 41 around the central axis 56, the striker 10 has a rotary joint 66 and a coupling element 67, whereby the coupling element 67 is firmly connected to the front hood 2 and the rotary joint 67 rotatably connects the actuator 41 with the coupling element 67. The rotary joint 67 can be formed, for example, as a ball bearing or in the form of a circumferential groove around the coupling element 67 and an elevation on the actuator 41 protruding corresponding to the central axis 56.

The control contour 51 extends around a circumference of the cylindrically formed actuator 41 and has a first ratchet contour 58, a second ratchet contour 61, a third ratchet contour 68 and a fourth ratchet contour 69. In the first position of the actuator 41 the guide element 57 is ratcheted in the first ratchet contour 58 or the third ratchet contour 68 and in the second position of the actuator 41 in the second ratchet contour 61 or the fourth ratchet contour 69 and the actuator 41 is thus ratcheted accordingly. The first and second position of the actuator 41 is only defined by means of the distance of the actuator 41 from the catch 4, or more precisely from the pivot point 23 of the catch 4, i.e. the actuator 41 can assume the first position if the guide element 57 is ratcheted in the first ratchet contour 58 or in the third ratchet contour 68 or assume the second position if the guide element 57 is ratcheted in the second ratchet contour 61 or in the fourth ratchet contour 69.

The striker 10 preferably has a striker spring 59 which is tensioned in the first and second position of the actuator 41 and keeps the actuator 41 pressed against the guide element 57 via the control contour 51.

The control contour 51 has an upper and a lower delimiter, whereby in the vicinity of the ratchet contours 58, 61, 68 and 69 tips of the upper delimiter are arranged in a displaced manner in respect of notches of the lower delimiter and thus at least a first displacement 62 and a second displacement 63 are formed. The first displacement 62 and the second displacement 63 cause the actuator 41 to be rotated during displacement from the first to the second position and from the second to the first position in the direction around the central axis 56 illustrated by the arrows 64 and 65.

If, as shown in FIG. 4, the actuator 41 is located in the first position, a displacement of the front hood 2 in the direction of the closed position of the front hood 2 causes a downward movement of the actuator 41 as shown in FIG. 4, in the first position, and the control contour 51 travels along the guide element 57, until the guide element 57 ratchets into the second ratchet contour 61. The guide element 57 glides along an ascending section of the control contour 51. A third displacement on the first ratchet contour 58, which is formed as the second displacement 63 causes the guide element 57 to impact on a surface of the upper delimiter oblique to the central axis 56 and the actuator 41 moves into the direction shown with the arrow 64. Shortly before the guide element 57 ratchets into the second ratchet contour 61, the control contour 51 impacts with the upper delimiter on the guide element 57 and movement of the front hood 2 is stopped with the actuator 41 by means of the coupling of the front hood 2. A return is preferably triggered which causes ratcheting of the guide element 57 into the second ratchet contour 61.

Starting from the second position of the actuator 41 shown in FIG. 5, a displacement of the front hood 2 in the direction of the closed position of the front hood 2 causes a downward movement of the actuator 41 and thus a deratcheting of the guide element 57 from the second ratchet contour 61. The first displacement 62 ensures that during a downward movement of the actuator 41 the guide element 57 impacts on a surface of the upper delimiter oblique to the central axis 56 and on the one hand the actuator 41 is moved into the direction shown with the arrow 64 or 65 and on the other hand brakes the front hood 2, whereby a haptic signal is generated for an operator of the safety device. If the front hood 2 is released following the deceleration, the striker spring 59 accelerates the front hood 2 upwards, whereby an upward movement of the actuator 41 is caused, whereby the control contour 51 travels along the guide element 57 until the guide element 57 ratchets into the third ratchet contour 68 as shown in FIG. 6. The guide element 57 glides along a descending section of the control contour 51. If the guide element 57 is ratcheted in the third ratchet contour 68, the actuator 41 is located in the first position.

Thus, in the pre-ratchet position of the catch a displacement of the front hood in the direction of the closed position causes a displacement of the actuator from the second position to the first position. A subsequent displacement of the actuator 41 from the first to the second position occurs similarly as for the aforementioned displacement in which the guide element 57 is transferred from the first ratchet contour 58 into the second ratchet contour 61, only that the guide element 57 is transferred from the third ratchet contour 68 into the fourth ratchet contour 69. FIG. 7 shows the actuator 41 in the second position, whereby the guide element 57 is ratcheted in the fourth ratchet position 69. A subsequent displacement of the actuator 41 from the second to the first position occurs similarly as for the aforementioned displacement in which the guide element 57 is transferred from the second ratchet contour 61 into the third ratchet contour 68, only that the guide element 57 is transferred from the fourth ratchet contour 69 into the first ratchet contour 58. FIG. 7 shows the actuator 41 in the first position, whereby the guide element 57 is ratcheted in the first ratchet contour 58.

FIG. 8, FIG. 9 and FIG. 10 show a further embodiment, whereby the construction of the safety device illustrated in FIG. 8 to FIG. 10 corresponds to the safety device illustrated in FIG. 1 to FIG. 3 to a great extent and is furnished with the relevant reference sign. The catch 4, the locking element 43, the pin 44, the counterpin 45, the electrical drive 5 also interact with the first electromotor 6 and the second electromotor 7 and the pawl 12 identically to as described for the exemplary embodiment according to FIG. 1 to FIG. 3. In contrast to the embodiment according to FIG. 1 to FIG. 3, in the embodiment according to FIG. 8 to FIG. 10 the striker 10 is executed differently.

FIG. 8 shows a cross-sectional view of the safety device 1 with a further configuration of a striker 71 of the hood latch 3. As in FIG. 2, the catch 4 in the position shown in FIG. 8 is located in the pre-ratchet position. In the embodiment shown in FIG. 8, the striker 71 has an actuator 72 aligned to the pawl 12 which can interact with a laterally protruding bolt 73 of the pawl 12 during depression of the front hood 2. The actuator 72 is located in the position shown in FIG. 8 in a first position in which the striker 71 engages with the catch 4 and the front hood 2 is locked and the actuator 72 is at a distance 76 from the bolt 73. Furthermore, the striker 71 has a cylinder 77 and a shaft 78, whereby the cylinder 77 is shiftably guided in the shaft 78. A striker spring 74 of the striker 71 acts on the cylinder 78 with a spring force which is greater than the weight force of the front hood 2 and thus holds the front hood 2 in the pre-ratchet position of the catch 4 in an elevated position.

By depression of the front hood 2 the front hood 2 can be transferred into a lowered position, as shown in FIG. 9, whereby the front hood 2 is displaced in the direction of the closed position of the front hood 2. This displacement of the front hood 2 in the direction of the closed position causes a displacement of the actuator 72 from the first position into an intermediate position of the actuator 72 shown in FIG. 9, whereby a gliding surface 75 of the actuator 72 glides along the bolt 73 and pushes it away from the catch 4 and releases the pawl 12 from the pre-ratchet contour 24.

The force which acts on the front hood 2 in the released position of the catch 4 starting from the catch spring element 32 is preferably considerably greater than the force which acts on the front hood 2 starting from the striker spring 74. This force can thus be twice or four times the weight force of the front hood 2. This ensures that an operator of the safety device 1 does not unintentionally transfer the catch 4 into the main ratchet position during an intentional unlocking of the front hood 2. Furthermore, thus during unlocking a comparatively great upward counterforce is generated which can be twice as high as the weight force of the front hood 2, for example, whereby a haptic signal can be generated to an operator of the front hood 2.

Starting from the pre-ratchet position of the catch 4 shown in FIG. 9 the catch 4 is rotated into an opening end position illustrated in FIG. 10 by means of the catch spring element 32 and the front hood 2 is transferred into an elevated position. In the elevated position of the front hood 2 the striker spring 74 is relaxed and the actuator 72 is arranged at a distance from the bolt 73 and assumes a second position. In this second position of the actuator 72 the striker 71 is released from the catch 4 and the front hood 2 is unlocked. The first and the second position of the actuator 72 are to be understood as relative positions to the bolt 73 or to the pivot point of the pawl 12.

Starting from the opening end position shown in FIG. 10, the catch 4 can be transferred into the pre-ratchet position by means of depression of the front hood 2. The catch 4 rotates in the closure rotational direction 22 beyond the pre-ratchet position to a turning point position which is reached at the end of the depression. During this movement of the catch 4 the actuator 72 passes the bolt 73. In an advantageous embodiment, the striker spring 74 acts on the front hood 2 in the turning point position of the catch 4 with considerably greater force than the catch spring element 32 via the catch 4 and the striker 71 acts on the front hood 2. This causes the actuator 72 to maintain a distance, preferably the distance 76 to the bolt 73 when the catch 4 is located in a position during a movement starting from the turning point position in the opening rotational direction 21 which it assumes in the pre-ratchet position so that the pawl 12 can ratchet into the pre-ratchet contour.

A different embodiment envisages that the bolt 73 meets an oblique sliding surface of the actuator 72 and the actuator 72 is laterally distorted and the actuator 72 can glide past the bolt and the pawl 12 is not pressed away from the catch 4 in an upward movement of the actuator 72. To this end, the actuator 72 can be elastically deformed. 

1. A safety device for a motor vehicle, which has a front hood with an open position and a closed position and a hood latch with a striker, wherein the hood latch includes: a catch with a pre-ratchet position and a main ratchet position in which the front hood is locked and closed, and an electrical drive, which causes switchover of the catch from the main ratchet position into the pre-ratchet position, and wherein the striker has an actuator, whereby in a first position of the actuator and in the pre-ratchet position of the catch the striker engages with the catch and the front hood is locked and in a second position of the actuator the striker is released from the catch and the front hood is unlocked, and the front hood is coupled with the actuator such that in the pre-ratchet position of the catch, displacement of the front hood in the direction of the closed position of the front hood causes displacement of the actuator from the first position to the second position.
 2. The safety device according to claim 1, wherein the front hood is manually displaceable in the direction of the closed position in the pre-ratchet position of the catch.
 3. The safety device according to claim 1, wherein the actuator is ratchetable and the striker has a control contour and a guide element, whereby the guide element interacts with the control contour such that a ratcheting of the actuator is enabled at least in the first position and/or the second position of the actuator.
 4. The safety device according to claim 1, wherein the front hood is coupled with the actuator such that in the pre-ratchet position of the catch a displacement of the front hood in the direction of the closed position causes a displacement of the actuator from the second position to the first position.
 5. The safety device according to claim 1, wherein the striker has at least a locking element and the catch encompasses the locking element in the pre-ratchet position and in the first position of the actuator.
 6. The safety device according to claim 1, wherein the catch assumes an opening end position with the pre-ratchet position in which the catch is immobile in the opening rotational direction.
 7. The safety device according to claim 1, wherein the catch has an opening end position in addition to the pre-ratchet position and the main ratchet position in which the catch is rotated into an opening rotational direction in respect of the pre-ratchet position.
 8. The safety device according to claim 1, wherein the hood latch has a pawl to lock the catch and a displacement of the actuator from the first position to the second position causes detachment of the pawl from the catch.
 9. The safety device according to claim 1, wherein the hood latch has a direct mechanical operative connection between the electrical drive and the catch during switchover of the catch from the main ratchet position into the pre-ratchet position.
 10. The safety device according to claim 1, wherein the hood latch has a direct mechanical operative connection between the electrical drive and the catch during switchover of the catch from the pre-ratchet position into the main ratchet position. 